Basic Biochemistry

What is Biochemistry?  Biochemistry is the study of the chemical interactions of living things.  Biochemists study the structures and physical properties of biological molecules. Often are involved in the manufacture of new drugs and medical treatments

Biochemistry: where chemistry and biology meet head-on  Living things require millions of chemical reactions within the body, just to survive.  Metabolism = all the chemical reactions occurring in the body.  Organic molecules: usually associated with living things. always contain CARBON. are “large” molecules, with many atoms always have covalent bonds (share electrons)

Composition of an Atom  Protons: Nucleus, positive charge  Neutrons: Nucleus, no charge  Electron: Energy levels, negative charge

Isotopes  Atoms of the same element with a different number of neutrons.  Benefits: the radiation given off of some isotopes can be used to treat cancer and kill bacteria that cause food to spoil.  Can also be used as “tracers” to follow the movement of substances thru the body.

Bonding  There are 2 main types of bonds:  Ionic: When atoms transfer electrons  Covalent: When atoms share electrons

Acids & Bases  Acids have a pH of 0-6  Bases have a pH of 7-14  Neutral = 7  What is the optimal pH of human blood?  7.4

Buffers  Substances that can absorb or release H + as levels fluctuate within living systems to help maintain a constant pH  Example: Carbonic Acid Bicarbonate (buffer that helps maintain pH of the blood)

Macromolecules of Cells  Macro = large  4 types of macromolecules in cellular biology 1. Carbohydrates 2. Lipids 3. Proteins 4. Nucleic Acids

Macromolecule #1: Carbohydrates  Sugars and groups of sugars  Purposes: energy and structure  Includes three types: Monosaccharide (1 sugar – quick energy) Disaccharide (2 sugars – short storage) Polysaccharide (many sugars – energy long storage & form structures)

Macromolecule #1: Carbohydrates  Polysaccharide Examples: Glycogen—glucose polymer stored for future energy needs. Found in liver, muscle and sperm, etc. Cellulose—glucose polymer used to form fibers for plant structures. Humans can’t digest (fiber). Most abundant organic molecule. Chitin—glucose polymer for exoskeletons of some crustaceans & insects.

Polysaccharides

Macromolecule #2: Lipids  Insoluble in water (think oil & water) 4 types: 1-triglycerides (fats & oils)  (long-term energy storage, insulation) 2-phospholipids (primary component of cell membrane) 3-steroids (cell signaling)  cholesterol molecules modified to form sex hormones. (e.g. testosterone, estrogen, etc.) 4-waxes (protection, prevents water loss)  Used mainly by plants, but also bees, some furry animals and humans.

Triglycerides

Phospholipids

Steroids

Waxes

Macromolecule #3: Proteins  Probably the most complicated of all biological molecules.  Serve the most varied purposes, including: Support structural proteins (e.g., keratin, collagen) Enzymes speed up chemical reactions Transport cell membranes channels, transporters in blood (e.g., Hemoglobin) Defense antibodies of the immune system Hormones cell signaling (e.g., insulin) Motion contractile proteins (e.g., actin, myosin)

Collagen

Antibodies

Cellular Transport

actin & myosin fibers in muscles Motion

Macromolecule #3: Proteins  The building blocks of proteins are AMINO ACIDS. There are only 20 types of Amino Acids.  There are millions of different proteins, and they are all built from different combinations of the 20 amino acids.  Amino acids join together to form peptides, polypeptides, and polypeptide chains.

Enzymes  Act as a lock and key  Specific: One substrate fits one enzyme  Reusable: One enzyme can break down many substrates

Competitive Inhibition  In competitive inhibition, the inhibitor binds to the same active site as the normal enzyme substrate, without undergoing a reaction.active site

Induced Fit Model  In this model, the enzyme changes shape on substrate binding. The active site forms a shape complementary to the substrate only after the substrate has been bound

Macromolecule #4: Nucleic Acids  Nucleotides: building blocks of nucleic acids. Each nucleotide contains  (a) phosphate molecule,  (b) nitrogenous base, and  (c) 5-carbon sugar  Several types of nucleic acids, including: DNA: deoxyribonucleic acid  Genetic material, double stranded helix RNA: ribonucleic acid  Genetic material, single stranded ATP: adenosine triphosphate  High energy compound

DNA

Nucleotide Structure

THE BIG PICTURE Chemistry is essential for life…